Can cataplexy cause your feet to swell?

It can: Similiar to the way someone with a foot drop from stroke usually has some degree of foot and ankle swelling compared to the other side. The principle is similiar - a loss of muscle tone or function doesn't allow the muscles to effectively help in pumping blood away from the area.

No: Cataplexy is a phenomenon of a sleep disorder, narcolepsy, where the body goes limp during intense emotions. There is no relationship with ankle swelling. Most meds used in narcolepsy or cataplexy do not cause this either, usually. Have your doctor evaluate this, as there may be vascular or kidney problems.

Possible: Due to the sudden lack of muscle tone this may also lead to the calf muscles being unable to contract and push the blood away from your feet toward your heart. This would lead to swelling in your feet. See your doctor for advice and consider compression hose.